TY - JOUR
T1 - P27 is regulated independently of Skp2 in the absence of Cdk2
AU - Kotoshiba, Shuhei
AU - Gopinathan, Lakshmi
AU - Pfeiffenberger, Elisabeth
AU - Rahim, Anisa
AU - Vardy, Leah A.
AU - Nakayama, Keiko
AU - Nakayama, Keiichi I.
AU - Kaldis, Philipp
N1 - Funding Information:
We thank all Kaldis lab members for their support and comments on the manuscript. We are very grateful to Piotr Sicinski for providing the Cdk2 shRNA construct. This work was supported by the Biomedical Research Council of A*STAR (Agency for Science, Technology and Research) , Singapore and in part by the Intramural Research Program of the NIH , the National Cancer Institute, Center for Cancer Research . SK was supported in part by the Japan Society for the Promotion of Science (JSPS) Research Fellowship in Biomedical and Behavioral Research at NIH.
PY - 2014/2
Y1 - 2014/2
N2 - Cyclin-dependent kinase 2 (Cdk2) is dispensable for mitotic cell cycle progression and Cdk2 knockout mice are viable due to the compensatory functions of other Cdks. In order to assess the role of Cdk2 under limiting conditions, we used Skp2 knockout mice that exhibit increased levels of Cdk inhibitor, p27Kip1, which is able to inhibit Cdk2 and Cdk1. Knockdown of Cdk2 abrogated proliferation of Skp2-/- mouse embryonic fibroblasts, encouraging us to generate Cdk2-/-Skp2-/- double knockout mice. Cdk2-/-Skp2-/- double knockout mice are viable and display similar phenotypes as Cdk2-/- and Skp2-/- mice. Unexpectedly, fibroblasts generated from Cdk2-/-Skp2-/- double knockout mice proliferated at normal rates. The increased stability of p27 observed in Skp2-/- MEFs was not observed in Cdk2-/-Skp2-/- double knockout fibroblasts indicating that in the absence of Cdk2, p27 is regulated by Skp2-independent mechanisms. Ablation of other ubiquitin ligases for p27 such as KPC1, DDB1, and Pirh2 did not restore stability of p27 in Cdk2-/-Skp2-/- MEFs. Our findings point towards novel and alternate pathways for p27 regulation.
AB - Cyclin-dependent kinase 2 (Cdk2) is dispensable for mitotic cell cycle progression and Cdk2 knockout mice are viable due to the compensatory functions of other Cdks. In order to assess the role of Cdk2 under limiting conditions, we used Skp2 knockout mice that exhibit increased levels of Cdk inhibitor, p27Kip1, which is able to inhibit Cdk2 and Cdk1. Knockdown of Cdk2 abrogated proliferation of Skp2-/- mouse embryonic fibroblasts, encouraging us to generate Cdk2-/-Skp2-/- double knockout mice. Cdk2-/-Skp2-/- double knockout mice are viable and display similar phenotypes as Cdk2-/- and Skp2-/- mice. Unexpectedly, fibroblasts generated from Cdk2-/-Skp2-/- double knockout mice proliferated at normal rates. The increased stability of p27 observed in Skp2-/- MEFs was not observed in Cdk2-/-Skp2-/- double knockout fibroblasts indicating that in the absence of Cdk2, p27 is regulated by Skp2-independent mechanisms. Ablation of other ubiquitin ligases for p27 such as KPC1, DDB1, and Pirh2 did not restore stability of p27 in Cdk2-/-Skp2-/- MEFs. Our findings point towards novel and alternate pathways for p27 regulation.
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U2 - 10.1016/j.bbamcr.2013.11.005
DO - 10.1016/j.bbamcr.2013.11.005
M3 - Article
C2 - 24269842
AN - SCOPUS:84890748013
SN - 0167-4889
VL - 1843
SP - 436
EP - 445
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
IS - 2
ER -